For present MEMS pressure sensors, regardless of a piezoresistive or capacitive type, a pressure-sensitive film needs to be exposed in air; otherwise, the pressure-sensitive film cannot make a sensitive reaction to external air pressure. Such a pressure-sensitive film is applied generally as an electrical capacitance polar plate or resistor, and because it must be exposed in air and cannot be disposed in a closed electrical cavity body, external electromagnetic interference will cause an influence on the output of the MEMS pressure sensor.